libsyscall/wrappers/open-base.c

   1 /*
   2  * Copyright (c) 2020 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <fcntl.h>
  25 #include <stdarg.h>
  26 #include <sys/param.h>
  27 #include <sys/types.h>
  28 #include <TargetConditionals.h>
  29
  30 #if !defined(__i386__)
  31
  32 #if TARGET_OS_OSX
  33 #include <stdbool.h>
  34
  35 /*
  36  * On macOS we have support for shimming calls to open the SystemVersion plist.
  37  * This support is enabled for specific (generally older) binaries from
  38  * libSystem_initializer()/__libkernel_init_late() by populating these function pointers
  39  * with the corresponding functions built into libsyscall_dynamic (see open-compat-shim.c).
  40  */
  41 extern bool (*system_version_compat_check_path_suffix)(const char *orig_path);
  42 extern int (*system_version_compat_open_shim)(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
  43     int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
  44     int (*openat_syscall)(int, const char *, int, mode_t),
  45     int (*fcntl_syscall)(int, int, long));
  46 #endif /* TARGET_OS_OSX */
  47
  48 #ifdef VARIANT_CANCELABLE
  49 int __open(const char *path, int oflag, mode_t mode);
  50 int __openat(int fd, const char *path, int oflag, mode_t mode);
  51
  52 #define OPEN_SYSCALL __open
  53 #define OPENAT_SYSCALL __openat
  54
  55 #if TARGET_OS_OSX
  56 int __fcntl(int fd, int cmd, long arg);
  57 int close(int fd);
  58
  59 #define FCNTL_SYSCALL __fcntl
  60 #define CLOSE_SYSCALL close
  61 #endif /* TARGET_OS_OSX */
  62
  63 #else /* VARIANT_CANCELABLE */
  64 int __open_nocancel(const char *path, int oflag, mode_t mode);
  65 int __openat_nocancel(int fd, const char *path, int oflag, mode_t mode);
  66
  67 #define OPEN_SYSCALL __open_nocancel
  68 #define OPENAT_SYSCALL __openat_nocancel
  69
  70 #if TARGET_OS_OSX
  71 int __fcntl_nocancel(int fd, int cmd, long arg);
  72 int __close_nocancel(int fd);
  73
  74 #define FCNTL_SYSCALL __fcntl_nocancel
  75 #define CLOSE_SYSCALL __close_nocancel
  76 #endif /* TARGET_OS_OSX */
  77 #endif /* VARIANT_CANCELABLE */
  78
  79 #ifdef VARIANT_CANCELABLE
  80 int
  81 open(const char *path, int oflag, ...)
  82 #else /* VARIANT_CANCELABLE */
  83 int
  84 open$NOCANCEL(const char *path, int oflag, ...)
  85 #endif
  86 {
  87         int opened_fd = 0;
  88         mode_t mode = 0;
  89
  90         if (oflag & O_CREAT) {
  91                 va_list ap;
  92                 va_start(ap, oflag);
  93                 /* compiler warns to pass int (not mode_t) to va_arg */
  94                 mode = va_arg(ap, int);
  95                 va_end(ap);
  96         }
  97
  98         opened_fd = OPEN_SYSCALL(path, oflag, mode);
  99 #if !TARGET_OS_OSX
 100         return opened_fd;
 101 #else /* TARGET_OS_OSX */
 102         if (opened_fd < 0) {
 103                 return opened_fd;
 104         }
 105
 106         /* check to see if system_version_compat is enabled for this process */
 107         if (system_version_compat_check_path_suffix == NULL) {
 108                 return opened_fd;
 109         }
 110
 111         /* check to see if the suffix of the path we opened matches one we are shimming */
 112         if (!system_version_compat_check_path_suffix(path)) {
 113                 return opened_fd;
 114         }
 115
 116         /* at this point we call into the version compat open shim and return values from there */
 117         return system_version_compat_open_shim(opened_fd, -1, path, oflag, mode, CLOSE_SYSCALL, OPEN_SYSCALL,
 118                    NULL, FCNTL_SYSCALL);
 119 #endif /* TARGET_OS_OSX */
 120 }
 121
 122 #ifdef VARIANT_CANCELABLE
 123 int
 124 openat(int fd, const char *path, int oflag, ...)
 125 #else /* VARIANT_CANCELABLE */
 126 int
 127 openat$NOCANCEL(int fd, const char *path, int oflag, ...)
 128 #endif
 129 {
 130         int opened_fd = 0;
 131         mode_t mode = 0;
 132
 133         if (oflag & O_CREAT) {
 134                 va_list ap;
 135                 va_start(ap, oflag);
 136                 // compiler warns to pass int (not mode_t) to va_arg
 137                 mode = va_arg(ap, int);
 138                 va_end(ap);
 139         }
 140
 141         opened_fd = OPENAT_SYSCALL(fd, path, oflag, mode);
 142 #if !TARGET_OS_OSX
 143         return opened_fd;
 144 #else
 145         if (opened_fd < 0) {
 146                 return opened_fd;
 147         }
 148
 149         /* check to see if system_version_compat is enabled for this process */
 150         if (system_version_compat_check_path_suffix == NULL) {
 151                 return opened_fd;
 152         }
 153
 154         /* check to see if the suffix of the path we opened matches one we are shimming */
 155         if (!system_version_compat_check_path_suffix(path)) {
 156                 return opened_fd;
 157         }
 158
 159         /* at this point we call into the version compat open shim and return values from there */
 160         return system_version_compat_open_shim(opened_fd, fd, path, oflag, mode, CLOSE_SYSCALL, NULL,
 161                    OPENAT_SYSCALL, FCNTL_SYSCALL);
 162 #endif /* !TARGET_OS_OSX */
 163 }
 164 #endif /* !defined(__i386__) */